sql - /usr/tmp, default path in UTL_FILE

Question

When i am searching for directories registered to UTL_DIR i am getting the following :

select value from v$parameter where name='utl_file_dir';

/usr/tmp, /usr/tmp, /oradata/hrtst/db/tech_st/11.2.0/appsutil/outbound/HRTS, /usr/tmp

Does this mean /usr/tmp is the directory for UTL_DIR ? also i cannot search for /oradata/hrtst/db/tech_st/11.2.0/appsutil/outbound/HRTS through winscp or putty.

Also i created a directory like

create or replace directory MY_DIR as '/usr/tmp';

and then i tried to write in this folder :

DECLARE
  fileHandler UTL_FILE.FILE_TYPE;
begin
  fileHandler := UTL_FILE.FOPEN('MY_DIR', 'test_file.txt', 'W');
  UTL_FILE.PUTF(fileHandler, 'Writing TO a file\n');
  UTL_FILE.FCLOSE(fileHandler);
EXCEPTION
  WHEN others THEN
     raise_application_error(-20000, 'ERROR: Invalid PATH FOR file.');
END;

anonymous block completed

though this block got executed succesfuly but no file got created in the directory when i checked.